All-polyethylene Tibial Components are Equal to Metal-backed Components: Systematic Review and Meta-regression

Abstract

Background Less than 1% of all primary TKAs are performed with an all-polyethylene tibial component, although recent studies indicate all-polyethylene tibial components are equal to or better than metal-backed ones. Questions/purposes We asked whether the metal-backed tibial component was clinically superior to the all-polyethylene tibial component in primary TKAs regarding revision rates and clinical functioning, and which modifying variables affected the revision rate.Methods We systematically reviewed the literature for clinical studies comparing all-polyethylene and metalbacked tibial components used in primary TKAs in terms of revision rates, clinical scores, and radiologic parameters including radiostereometric analysis (RSA). Meta-regression techniques were used to explore factors modifying the observed effect. Our search yielded 1557 unique references of which 26 articles were included, comprising more than 12,500 TKAs with 231 revisions for any reason. Results Meta-analysis showed no differences between the all-polyethylene and metal-backed components except for higher migration of the metal-backed components. Metaregression showed strong evidence that the all-polyethylene design has improved with time compared with the metalbacked design. Conclusions The all-polyethylene components were equivalent to metal-backed components regarding revision rates and clinical scores. The all-polyethylene components had better fixation (RSA) than the metal-backed components. The belief that metal-backed components are better than all-polyethylene ones seems to be based on studies from earlier TKAs. This might no longer be true for modern TKAs. Level of Evidence Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Total knee arthroplasty in patients with hypersensitivity to metals

“…By using the abovementioned type of implant, we had no complications, and we did not observe critical situations at midterm follow-up also regarding the use of an all-polyethylene tibial component. The clinical outcomes were substantially comparable to our previously reported data regarding the same implant with standard Cr-Co femoral components and metalback tibial baseplate in the same period [20], and in line with the most recent series [31,32].…”

“…Oxinium is a wellknown material, consisting in a nickel-free metal alloy with an oxide layer conferring bearing properties of the ceramic without the fracture risk related to brittleness [26][27][28]. The tibial component was made entirely of polyethylene (PE) without metalback; several papers during the last decades reported satisfactory results of all-polyethylene components in terms of tribologic behaviour and survivorship [29][30][31][32]. All the implants, available as cruciate retaining (CR) or posterior stabilized (PS) were cemented ( Fig.…”

Monoblock all-polyethylene tibial components have a lower risk of early revision than metal-backed modular components

“…In contrast, as demonstrated by radiostereometric analysis (RSA) techniques, the monoblock all-polyethylene tibial component has less component migration and better tibial fixation than fixed, metal-backed designs (Norgren et al 2004, Hyldahl et al 2005, Nouta et al 2012b). This would theoretically decrease or eliminate backside wear and the possibility of eventual revision.…”

Availability of Total Knee Arthroplasty Implants for Metal Hypersensitivity Patients

“…Furthermore, in regards to the tibia, all polyethylene tibial components can also be deemed to be “hypersensitivity-friendly”. An all polyethylene option has been shown in recent studies to have similar outcomes to modular tibial components18). These components have the effect of reducing cost and exposure to metal allergens when used in this subset of patients.…”